Apparatus for propelling fluid, especially for propulsion of a floating vehicle

ABSTRACT

A propeller has a number of blade surfaces or winglets extending helically around its rotational axis in the most streamlined manner. The winglets gradually project at an increasing distance outward with an arcuate shape, each defining a rearwardly concave channel that increases in volume and degree of encirclement rearward on the propeller. In the front of the propeller, the winglets are shaped so that they have edges angled obliquely and diagonally that conformingly and without cavitation cut into the water and cause it to flow smoothly in the channels. In the middle of the propeller, the winglet edges extend rearward so that water entrained in the channel is directed rearward without centrifugal loss. In the rear portion of the propeller, the channels narrow and reduce in volume so as to expel the water from the concavity.

FIELD OF THE INVENTION

The present invention relates to the field of fluid propulsion, and,more particularly, to devices that propel water or other fluids, orfloating vehicles that are propelled by such devices.

BACKGROUND OF THE INVENTION

A variety of devices are known for moving fluids such as water,including a variety of pumps and propeller designs. In the field offluid propulsion, motor-driven propellers often used to move a marinevehicle, such as a ship or a submarine, through water. These propellerstypically consist of a twisted airfoil shape, similar to those used asaircraft propellers, and are often only partially submerged in waterwhen operated.

An example of a propeller having a twisted airfoil shape is described inU.S. Pat. No. 4,767,278. One problem associated with the twisted airfoilshape of this type is that fluid is expelled laterally away from theaxis of rotation as the propeller is rotated. The kinetic energy of thiscentrifugal loss does not serve to propel the vehicle forward, becausethe fluid is not impelled rearward to any degree, but mainly radiallyaway from the axis of rotation. Therefore, propellers of this type arenot efficient and result in wasted energy and resources used to drivethe propeller.

Another problem associated with the twisted airfoil shape is cavitation,which often occurs at various points over the length of the propeller asit is rotated at different speeds. Cavitation stems from formation ofvapor bubbles in a region where the pressure of the liquid falls belowits vapor pressure, and can cause a great deal of noise, damage to thepropeller, and vibration, as well as a loss of efficiency.

Generally, prior art propellers in various forms have used the samebasic shape and design for over a hundred years, and these designs arestill affected by serious problems, e.g., cavitation at different pointsat certain speeds, with a consequent erosion and vibration of itsblades, centrifugal loss of fluid, general inefficiency due to drag orother factors, and configurations that limit the speed of the vessel.

As an alternate design approach, various screw propellers have beenproposed that provide a greater surface contacting the water. Forexample, U.S. Pat. No. 941,923 to Hoffman discloses a boat with ascrew-shaped propeller. Generally these screw propellers suffer fromsurface area drag, as well as suffering from the same problem of lateralcentrifugal fluid loss and large swirling or vortices that squander thekinetic energy imparted to the water.

SUMMARY OF THE INVENTION

It is accordingly an object of the present invention to provide apropeller that does not have the drawbacks of the prior art. An objectof the present invention is to maximize the efficiency of the propellerby minimizing centrifugal or lateral loss of fluid from the propellerbody.

Another object of the invention is to prevent cavitation on surfaces ofthe propeller.

Still another object of the propeller of the present invention is toprovide a more streamlined design of propeller that reduces drag andefficiently thrusts fluid primarily in a rearward direction.

In accordance with an aspect of the present invention, a propeller issupported on a floating body so as to be substantially completelysubmerged in water and rotatable about an axis of rotation to propel thefloating body in said water in a forward direction of movement. Thepropeller comprises a plurality of winglets or blade surfaces supportedon the floating body for rotation about the axis of rotation. Each ofthe winglets extends in a generally spiral path about the axis ofrotation and has a first surface facing generally rearwardly and asecond surface facing generally forwardly. The first surface of eachwinglet and the second surface of a respective next adjacent one of thewinglets define therebetween a fluid passage space extending generallyspirally around the axis of rotation. The fluid passage space having avarying volume defined as a space radially inward of the winglet. In aforward portion of the winglet, the volume of the fluid passage spacecontinuously increases rearwardly, and, in a rearward portion of thewinglet, the volume of the fluid passage space reduces continuouslyrearwardly.

According to another aspect of the invention, a propeller is supportedon a floating body so as to be completely submerged in water androtatable about a longitudinal axis of rotation for propelling thefloating body in said water. The propeller comprises a shaft rotatablysupported on the floating body. The shaft has a forward front end and arearward back end, and the shaft is driven so as to rotate about thelongitudinal axis. Three propulsion structures are supported on andextend in a generally spiral path about the shaft, and are rotationallystaggered with respect to one another. Each of the propulsion structureshas a fluid contact surface with a surface width measured along thefluid contact surface from a radially inward end portion to an outwardedge portion. The fluid contact surface has a forward engaging portion,an intermediate fluid entraining portion, and a rearward exhaustportion. The surface width of the fluid contact surface increases fromthe engaging portion to the intermediate fluid entraining portion, anddecreases from the intermediate fluid entraining portion to the exhaustportion. The fluid contact surface in the intermediate fluid entrainingportion is concave and inwardly and rearwardly disposed so as toradially inwardly enclose a spiral fluid flow volume, with the fluidcontact surface being shaped such that cross-sections thereof in a planeperpendicular to the longitudinal axis extend curvingly rearward adistance at least as great as a radially outward extension distance ofthe fluid contact surface.

According to still another aspect of the invention, a propeller issupported on a floating body in water so as to impel said floating bodyin a forward direction of movement. The propeller comprises a pluralityof winglets supported fixedly with respect to each other so as to rotatetogether about a longitudinally extending axis of rotation. Each of saidwinglets comprises a winglet body portion extending generally spirallyabout the axis of rotation and having a generally forwardly-disposedforward surface and a generally rearwardly-disposed rearward surface.The forward and rearward surfaces meet in an acute-angle winglet edgethat also extends generally spirally about said axis of rotation. Therearward surface is concave over at least a longitudinal portion of alongitudinal length of the winglet so as to define a generally rearwardfacing channel rearward of the winglet body portion such that therearwardly concave rearward surface has a forwardmost channel surfaceportion at a forwardmost part of the channel. The longitudinal portionincludes a forward intake portion, a retention portion rearward thereof,and an expelling portion rearward of the retention portion. In theintake portion, the winglet edge is oriented such that, as the propelleris rotated, the winglet edge passes into the water with a conformingflow from the winglet edge over the forward and rearward surfaces, and aportion of the water flows into the channel. From the intake portion tothe retaining portion, the forwardmost channel surface portion of therearward surface and the winglet edge extend continuously obliquelyrearward, and the winglet edge extends continuously obliquely rearwardlymore steeply than the forwardmost channel surface portion, and therearward surface widens and defines the channel to as to be wider in theretaining portion. In the retaining portion, the winglet edge isoriented such that the rearward surface contiguous thereto extendsrearward in a direction that differs from the longitudinal direction byno more than the acute angle. In the expelling portion, the channelbecomes narrower than in the retention portion. According to anotheraspect of the invention, a propeller has a plurality of wingletsextending generally spirally about its rotational axis. Each wingletdefines a fluid flow space that extends generally spirally around therotational axis. The length of the winglet to its outward edge increasescontinuously rearwardly from a minimum extension at the front end of thewinglet to a maximum extension in a rearward portion of the propeller,and then continuously decreases rearwardly therefrom to the rearward endof the winglet.

The fluid flow space has a cross-section relative to its spiral paththat is generally circular in a forward portion and in an intermediateportion of the propeller, and this cross-section increases in diameterrearwardly.

The winglet has a rearward facing curved surface ending in its edge. Thecurved surface in the forward portion of the propeller extends along anincreasing arc of the circumference of circular cross-section of thefluid flow space, and reaches at least approximately 180 degrees of thearc in the intermediate portion, where the surface provides a trailingsurface leading to the edge that is substantially parallel to therotational axis of the propeller.

The winglet preferably increases in extension beyond the 180 degrees ofarc but extends rearwardly outwardly of the circular cross-section. In arearward portion rearward of a position where the maximum extension ofthe winglet is reached, the winglet is radially inwardly compressed sothat the cross-section of the fluid flow space becomes generally an ovalshape that continues to reduce in size as the winglet extensiondecreases rearwardly, with the longer axis of the oval extendinglongitudinally of the propeller, with the winglet maintaining thetrailing edge portion of the curved surface generally extendinglongitudinally rearwardly.

Other objects and advantages of the invention herein will becomeapparent in the specification below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a boat employing a propeller according to anembodiment of the present invention.

FIG. 2 is a side view of a propeller-supporting structure on a boat,with some of the housing cut away to show its inner workings.

FIG. 3 is a front view of the boat as seen in FIG. 1.

FIG. 4 is a left view of the propeller of FIG. 1.

FIG. 5A is a detailed right-side view of the propeller of FIG. 1.

FIG. 5B is a cross-sectional view as in FIG. 5A taken at a verticalplane through a longitudinal centerline of the propeller.

FIG. 6 is a side view of a single winglet of the propeller view as inFIG. 5.

FIG. 7 is a graph illustrating variation of the surface width of thewinglet over the length of the propeller.

FIG. 8 is a side view of the single winglet of FIG. 6, with variouscross-sectional planes perpendicular to the axis of rotation identified.

FIG. 9 is a front end view of the winglet of FIG. 8.

FIG. 10 is a series of forward looking cross-sectional views of thewinglet of FIG. 8 taken along lines B₁ to B₉.

FIG. 11 is a series of detailed cross-sections of the winglet of FIG. 10taken through a vertical plane perpendicular to its axis of rotation.

FIG. 12 shows a series of cross-sections A₁-A₁₄ of the propeller ofFIGS. 4 and 5A.

FIG. 13 is a rear cross-sectional view of the propeller of FIG. 1through the supporting shaft looking forward.

FIG. 14 is a detail view of an exemplary cross-section of a winglet of apropeller of the invention.

FIG. 15 is a diagram of the rotational angle location of the midpoint ofthe winglet base and the trailing edge of the propeller.

FIG. 16 is a diagram showing conforming flow over a portion of a wingletaccording to the invention.

FIG. 17A is a diagram showing retention of water by the winglet in theretention portion of the propeller.

FIG. 17B and FIG. 17C are examples of cross-sections perpendicular tothe angle of attack.

FIG. 18 is a side view of a floating vessel having a propeller of analternate embodiment of the invention.

FIG. 19 is a side view of a floating vessel having a propeller of stillanother alternate embodiment of the invention.

FIG. 20 is a detailed side view of the propeller of FIG. 19.

FIG. 21 is a detailed rearward-looking view taken from plane A-A of FIG.20.

FIG. 22 is a detailed forward-looking rear view of the propeller of FIG.19.

FIG. 23 is a cross-sectional side view of the propeller of FIG. 19 takenthrough a vertical plane extending through its axis of rotation.

FIG. 24A and FIG. 24B are a series of cross-sections of the propeller ofFIG. 23 taken at planes C₁ to C₁₇ perpendicular to the axis of rotationof the propeller.

FIG. 25 is a side view of a floating vessel having a propeller of stilla further alternate embodiment of the invention.

FIG. 26 is a side view of still another embodiment of propeller systemaccording to the invention.

FIG. 27 is a rearward-looking front view of the propeller of FIG. 26.

FIG. 28 is a forward-looking rear view of the propeller of FIG. 26 takenfrom plane B-B.

FIG. 29 is a cross-sectional view of the propeller of FIG. 26 along itslongitudinal centerline.

FIG. 30 is a side view of another embodiment of propeller system.

FIG. 31 is a front view of the propeller system shown in FIG. 30.

FIG. 32 is the rear view of the propeller system shown in FIG. 30.

FIG. 33 is a cross-sectional view of the propeller system of FIG. 30along its longitudinal centerline.

FIG. 34 is a series of cross-sections D₁-D₄ of the propeller system ofFIGS. 30 to 33.

FIG. 35 is a series of cross-sections E₁-E₈ of another embodiment ofpropeller with thickened walls of the winglet at its forward end.

FIG. 36 is a series of cross-sections F₁-F₈ of still another embodimentof propeller, also with thickened walls of the winglet at its forwardend.

FIG. 37 shows a side view of another embodiment of propeller system witha propeller in a waterjet configuration.

FIG. 38 is a front view of the propeller system shown in FIG. 37.

FIG. 39 is a rear view of the propeller system shown in FIG. 37.

FIG. 40 is a cross-sectional view of the propeller of FIG. 37 along itslongitudinal centerline.

FIG. 41 is a series of cross-sections G₁-G₅ of the propeller of FIG. 37.

FIG. 42 is a side view of still another high speed embodiment ofpropeller, with an intubation.

FIG. 43 is a front view of the propeller of FIG. 42.

FIG. 44 is a rear view of the propeller of FIG. 42.

FIG. 45 is a cross-sectional view of the propeller of FIG. 42 along itslongitudinal centerline.

FIG. 46 is a series of cross-sections of the propeller of FIG. 42 at theplanes H₁-H₁₄ in FIG. 45.

FIG. 47 is a side view of still another embodiment of propeller systemthat is similar to the propeller of FIG. 30 but with intubation.

FIG. 48 is a front view of the propeller system shown in FIG. 47.

FIG. 49 is the rear view of the propeller system shown in FIG. 47.

FIG. 50 is a cross-sectional view of the propeller of FIG. 47 along itslongitudinal centerline.

FIG. 51 is a series of cross-sections taken at planes I₁-I₄ of thepropeller of FIG. 47.

FIG. 52 is a side view of a further alternate embodiment of propellersystem that is a reversible embodiment with a T-section of the wingletedge.

FIG. 53 is a front view of the propeller of FIG. 52.

FIG. 54 is a rear view of the propeller of FIG. 52.

FIG. 55 is a cross-sectional view of the propeller of FIG. 52 along itslongitudinal centerline.

FIG. 56 shows cross-sections of the propeller of FIG. 52 at planesJ₁-J₉.

FIG. 57 is a side view of another embodiment of propeller system with abulbous nose and intubation.

FIG. 58 is a front view of the propeller of FIG. 57.

FIG. 59 is a rear view of the propeller of FIG. 57.

FIG. 60 is a cross-sectional view of the propeller of FIG. 57 along itslongitudinal centerline.

FIG. 61 is a series of cross-sections of the propeller of FIG. 60 atplanes K₁-K₉.

FIG. 62 is a side view of another embodiment of propeller system thathas winglets around a solid shape.

FIG. 63 shows a front view of the propeller of FIG. 62.

FIG. 64 shows a rear view of the propeller of FIG. 62.

FIG. 65 is a cross-sectional view of the propeller of FIG. 62 along itslongitudinal centerline.

FIG. 66 shows cross-sections of the propeller of FIG. 62 in planesL₁-L₉.

FIG. 67 shows a side view of another embodiment of propeller system thatis enclosed within a fixed, non-rotating frame or grille.

FIG. 68 is a front view of the propeller of FIG. 67.

FIG. 69 shows the propeller mounted within the frame, which is sectionedalong the longitudinal centerline of the propeller.

FIG. 70 shows a rear view of the propeller of FIG. 67.

FIG. 71 shows cross-sections of the propeller of FIG. 67 at planesM₁-M₆.

FIG. 72 shows another longitudinal cross-sectional view of a variant ofthe propeller of FIG. 67.

FIG. 73 shows a front view of the propeller of FIG. 72

FIG. 74 shows a rear view of the propeller of FIG. 72.

FIG. 75 shows a side view of another embodiment of propeller systemhaving a reversible, symmetrical, coreless propeller.

FIG. 76 shows a front view of the propeller of FIG. 75.

FIG. 77 shows a rear view of the propeller of FIG. 75.

FIG. 78 is a cross-sectional view of the propeller of FIG. 75 at itslongitudinal centerline.

FIG. 79 shows a series of cross-sections of the propeller of FIG. 75 atplanes N₁—N₉.

FIG. 80 is a side view of another embodiment of propeller systemconfigured for use at a very high or ultra-high speed.

FIG. 81 is a cross-sectional view of the propeller of FIG. 80 along itslongitudinal centerline.

FIG. 82 shows a series of cross-sections of the propeller of FIG. 80 atplanes O₁-O₅. FIG. 83A is an outline view of the propeller shown in FIG.1.

FIG. 83B is an outline view of the propeller shown in FIG. 19 (20).

FIG. 83C is an outline view of the propeller shown in FIG. 30.

DETAILED DESCRIPTION

As best seen in FIG. 1, at least one propeller or propeller 11 issupported under a vessel 13 floating in water 15. The propeller 11 iscompletely submerged, and is driven by a motor (not shown) of the vessel13, which causes the propeller 11 to rotate in a clockwise direction 17when viewed looking forward along an axis of rotation 19, so as topropel the vessel 13 in a forward direction A. A pointed front end 23 ofthe propeller 11 extends in the forward direction.

Referring to FIGS. 2 and 3, rudder structure 29 of the vessel 13receives and rotatably supports a shaft portion 26 extending from therearward end 25 of the propeller 11 into sealed receiving sleeve 27 ofthe rudder 29. Shaft 26 has fixed thereon a toothed cylindrical gear 31that meshes with a worm gear 33 on a shaft 35 from the motor (notshown), or the shaft 26 may be driven by any other system for turningpropeller shafts known in the art. Pivoting rudder vane 28 is controlledby the user of the vessel to direct the movement of the vessel, as isalso well known in the art.

Overview of Propeller Design

Referring to FIGS. 4, 5A and 5B, the propeller 11 comprises centralshaft 25 supporting thereon a plurality, in this embodiment three,propulsion elements 41, 43 and 45, herein referred to as winglets orblade surfaces, which extend generally helically around the shaft 25. Inthe preferred embodiment, the propeller 11, including the winglets 41,43 and 45, is an integral or composite-material unibody device, meaningthat it is formed of one piece of relatively rigid material, e.g.,composite materials, metal and/or plastic, and has no internal movingparts, except for its being supported for rotation in the rudderstructure 29.

Each winglet 41, 43 and 45 defines an associated respective spiralingfluid flow space in a concave, generally rearwardly-disposed, channelface of the winglet.

In a forward part of the propeller, generally described as an intakeportion, the propeller rotates and advances in the water, causing eachwinglet edge to meet the water so as to gradually cut into and entrainthe water in the associated channel, where the water is directedrearward, with conforming non-cavitating flow over the front and rearsurfaces of the winglets. In the intake portion, the winglets increasein length, and the volume of the channels subtended by the wingletsincrease gradually and continuously to accommodate the increasing amountof water being brought in to the channels by the cutting of the wingletedges.

At the front tip of the propeller, the fluid flow space or channel issmall or nonexistent and the small winglet surfaces end in edges thatinitially start straight or slightly spiral around the longitudinal axisand then gradually increase their helix to about a 45 degree angle, andremain at that angle for most of the length of the active/propellingsegment. The channels increase in cross-section (the cross-section beingeither taken in a plane normal to a respective spiral path of eachchannel behind the respective winglet, or taken in a plane extendingthrough the longitudinal axis) with consequently increasing volumerearward. The winglets have a generally curved cross-sectional shape,and the concave faces of the winglets are tilted at an angle in thedirection of rotation of the propeller. The edges act as cutting edgesthat cut into the stationary water and cut from the surrounding water aportion of the water that is then entrained in the fluid flow space andaccelerated in a spiral flow therein to the rear.

The curved shape of the winglets in this embodiment subtends, or isapproximately a portion of, an arc of a circle. As the winglets growlonger rearward, the surfaces of the winglets extend further along thearc of the generally circular shape of the fluid flow space, and theradius of the arc increases as well, with the channel subtending orconstituting a flow space that can be described as a generally conicalspace that is wrapped spirally about the axis of rotation of thepropeller.

In a middle portion of the propeller, generally described as a retentionportion, the winglets are shaped so that the channels reach theirmaximum radial width.

In this retention portion, the outer surface of the edges of thewinglets extend approximately straight rearward parallel to thelongitudinal direction, or, expressed more geometrically, the outersurfaces are tangent to a theoretical cylinder around the axis ofpropeller rotation. Here water is not taken into the channels, but thewater already inside the channels is enclosed and guided so as to flowspirally in the channels. Water outside the winglets flows over theouter surfaces of the rotating winglets conformingly, withoutcavitation, and without being drawn in to the channel.

The water inside the channel is substantially prevented from centrifugaloutward flow from the channel by the extension of the winglet tosurround a substantial portion of the volume of the channel, with thelongitudinal distance from the front of the flow space to the rear tipof the winglet being at least half the radial width of the flow space asbounded by the winglet, with the curve of the winglets being an arc ofapproaching 180 degrees or more. Also in the retention portion, theinward surfaces of the edges of the winglets cease to be a cutting edge,and rather become a trailing edge surface of the winglet channels thatis oriented so that it deflects or directs flow of water being pushedcentrifugally outward in the channel to pass along the inside surface ofthe winglet, and to flow off the winglet rearwardly, and not laterallyoutward, which would squander energy conferred to the water by thepropeller.

The rear part of the propeller, which is rearward of the retentionportion, is here generally described as the exhaust portion. Thediameter of the cross-section increases rearwardly to a maximum point,and then the fluid flow space channel narrows radially so that itbecomes longitudinally oblate and generally oval in shape, with thepitch of the spiral path increasing so that fluid leaves the propellerat an accelerated rate. The winglets' curvature pinches graduallyradially inward so that the channel narrows radially and lengthenslongitudinally, incrementally reducing the volume of the channel throughwhich the water is flowing, with the result that the water passingthrough it is expelled substantially directly rearwardly at high speedfrom the channel at the rearward edge of the winglet, which is orientedto extend generally directly longitudinally rearward. The spiral path ofthe channel also here increases in pitch so that the rearward movementof water flowing through the channel is accelerated.

The propeller and all its surfaces are designed to preserve continuityof flow of the fluid passing over it, and to minimize disturbance of thestate of the fluid. This is achieved by eliminating abrupt changes oruneven surfaces, which would tend to create turbulence in the water flowor stagnation, and a resulting loss of efficiency. The propeller 11 ofthe invention provides the following functions and advantages:

-   -   it efficiently pierces and hydrodynamically displaces fluid;    -   it cuts and collects fluid gradually and efficiently without        creating turbulence or stagnation, etc.;    -   it propels the fluid substantially directly rearwardly,        accelerating it gradually, smoothly, efficiently and forcefully;    -   it contains the fluid laterally and reduces loss of the fluid        centrifugally;    -   it discharges the fluid rearwardly from the propeller in a clean        and uniform flow;    -   it provides a contour or external envelope of the propeller that        reduces turbulence and drag of the device while it travels        through the fluid; and    -   it performs the above functions seamlessly using one        compound/composite unibody propeller design and device in the        most streamlined manner possible.

The three main portions described above, i.e., intake, retention andexhaust portions, are primary features of the propeller or propeller 11,but in more detail, referring to FIGS. 4 and 5, the propeller orimpelpropeller 11 conceptually can be divided into five longitudinalsections or segments A to E, each focused on respective specificfunctions. The transition between the sections is smooth and continuous,with the smooth shape of the winglets, and there may be some overlap ofthe functions of the segments.

The first segment is a penetrating section A, i.e., the pointed tip 23,which helps to make the entry into the fluid as efficient andnon-turbulent as possible. It is an object of the present design tominimize any turbulence or any differences of pressure or flow speedanywhere on the propeller that result in cavitation, noise, drag orother inefficiency of flow of the fluid as well as of propulsion of thevessel. The sharp nose of the propeller 11 does this, and the initialoutward extension of the winglets is in a path that minimizes turbulencearound the rotating front tip 23.

The second segment is the intake section B. In the intake section B, aleading edge of each of the winglets initially extends longitudinallyand projects radially outwardly, and then smoothly transitions to becomeobliquely disposed front and/or lateral winglet edges, with a surfacethat gradually becomes laterally wider and rearwardly concave, so as tocollect the fluid and take it inside the volume of a channel passagedefined by the inward and rearward concave surface of the winglet of thepropeller, as described above. The subtended volume in the channel inthis area continuously and monotonically increases rearwardly of thepropeller.

The third segment is the retention or intermediatecompressing/propelling section C that follows intake section B, asdescribed above. Compressing/propelling retention section C propellerstarts at about where the lateral extension starts, and encapsulates orencloses the fluid in the spiraling channel volume that is formedbetween two adjacent blades/winglets. The channel flow space in thissection is diagonal in a spiral or helical path in which the water flowsand is accelerated further. Section C is also described as the retentionsection, because the channel volume is largely bounded radiallyoutwardly by the rearward extension of the winglets, which block theradial outward flow of water in the channel due to centrifugal forcecreated by rotation of the propeller. Here the increase of the volume ofthe channel slows or stops altogether.

The fourth segment is the exhaust section D, where the edge of theblades/winglets pinch inward form a rearward directed opening in thechannel directed substantially straight to the back of propeller 11,causing the water in the winglet channel to flow rearward from thepropeller 11. The channel narrows and the spiral pitch increases in thissection, accelerating the expulsion of water rearward.

The fifth section is a trailing section E, in which the winglets end byextending at a sharp angle relative to the longitudinal axis so as torelinquish the fluid flow to run along the cylindrical shaft 25. Thewinglets in this segment extend longitudinally straight rearwardly, andthey have a smaller concavity or cupping than the forward sections so asto cause the trailing edge of each winglet to release the fluid. Thelast segment guides the flow as much as possible to the radial center,thus smoothing the flow. Any rotating device forms a vortex, and thussome turbulence, which uses energy and creates inefficiency, but thispropeller design reduces or eliminates the turbulence formed at the rearend of the propeller. In embodiments where the drive is not connected tothe shaft at the rear of the propeller, the rear end of the propeller 11preferably tapers down to a sharp point, not present in the embodimentof FIG. 5A or 5B.

The intake and retention segments B and C are somewhat integrated infunction, as are all the segments with the adjacent sections, as allshare the channels that spiral around the propeller and the sectionssmoothly transform each into the next without a suddenturbulence-provoking change. Variants of the propeller 11 can be made inwhich the segments are integrated fully among themselves, or they may bedefined and more clearly compartmentalized. Because of the seamlessconstruction of the propeller 11 and its winglets, it can be consideredto not have segments, but just one continuous construction, whichfulfills all five or the middle three of the segment functions. Also, apropeller or propellers may make use of only one or two of theabove-described functional segment structures advantageously.

Because of the integration of these segments the propeller presentedhere can be described as a continuous propeller in contrast to the“fragmented” or “flat” propeller in common current use.

Because of its shape and mode of operation, and because it includes inits design an impeller as well as a propeller component, the propeller11 can be technically and more precisely described as an axial, gradualimpelpropeller, with variable helically-pitched gradual andcontinuous-edge blades or winglets at both ends at sharp angles to itsaxis, of a specific shape.

The design of the exterior envelope shape of the propeller 11 is to adegree determined by the speed at which it is expected to move forwardin the water. When the propeller is a very fast or super-fast variant,(as used especially in high performance vessels), it is slim and long,with the purpose being reaching the highest speed attainable, especiallyat high rotational speeds, which gives the fastest volume of fluidexpelled for the smallest cross-section and therefore results in theleast resistance. As shown in FIG. 5B, the outer envelope of therotating propeller 11 resembles a sharp, aerodynamic generally“football” shape of rotation, wherein the forward end of the propelleris helicoidal and defined within a substantially conical envelope withan acute peak angle. The conical forward end shape serves to avoid astagnation point ahead of the propeller. In addition, the envelopecircumscribing the propeller at the rear end tapers inwardly in a rearconical envelope with an acute apex angle, preferably slightly lessacute, i.e., a greater angle of taper relative to the longitudinal axis,than the apex angle of the front conical envelope, all these parametersbeing variable and dependent on the specific needs or the requirement ofits particular design.

In different variants for slower movement or for greater volume offluid, the propeller can take different forms that are still similar tothe concept and design of FIGS. 4 and 5 but with different proportionsor ratios of the exterior envelope, as will be discussed further below.In other variants, the first and last segments A and E may be eliminatedin the propeller, especially in variants where the front or rear ends,or both, of the propeller are shafts driven by a motor of the vessel.

Configuration of Winglets

Referring to FIG. 6, the diagram shows a single exemplary winglet 41without the other winglets attached to the central shaft 25. It will beunderstood that in the first embodiment three winglets of thisconfiguration are on the shaft 25, and that each of the winglets 41, 43,and 45 in the embodiment shown in FIG. 5 has the same structure andconfiguration as the winglet 41 shown in FIG. 6, except rotated 120degrees relative to each other so as to each have a separate spiral patharound the longitudinal axis around the propeller 11. The relativepositions of the different winglets 41, 43 and 45 in the completepropeller may be seen in the various section views of FIG. 12, and alsoin the rear view of the propeller 11 shown in FIG. 13. The singlewinglet structure shown is exemplary, but could also function as apropeller to some degree, although it is not rotationally balanced.

As seen in FIG. 6, each winglet 41 comprises essentially a structurehaving a radially-inward proximal portion 51 attached to the centralshaft 25. Alternatively, the winglet 41 may be located simply at thelongitudinal axis and fixedly connected with the other winglets 43 and45 so as to form a unified structure propeller 11 that does not have acentral shaft.

The winglet 41 extends outwardly radially from inward proximal portion41 to an outward edge 53 that extends spirally about the longitudinalaxis of the propeller 11. The winglet body itself has two surfaces, agenerally forward and outwardly disposed surface 55 and a generallyrearwardly and inwardly disposed surface 57 that extends essentiallycontinuously from the forward end 59 of the winglet all the way to therearward end 61 of the winglet. The winglet 41 extends in a generallyspiral path about the axis of the propeller, but with certain variationsto aid in the flow of fluid around the propeller.

Referring to FIG. 7, the winglet has a lateral surface width S asmeasured radially outward along its inside surface 57 from theradially-inward proximal end 51 or from the axis of the propeller 11 tothe outward edge of the winglet. The variation in this dimension S asmeasured along the curved surface of the rearward surface 57 of thewinglet is illustrated in the graph of FIG. 7, which shows the wingletessentially uncoiled and flat for measurement. This surface widthdimension S increases gradually from front end 59 where the winglet 41initially emerges from the sharp front point 23 of the propeller togradually and approximately linearly increase rearward of the propeller11. The dimension S increases rearward to a point approximately 0.6-0.75in this embodiment L, where L is the length of the winglet from frontend 59 to rear end 61 measured rearwardly. Rearward of this, the wingletsurface dimension S curves and tapers inward much more sharply than theangle of linear increase, reducing to essentially zero within the last0.25 L of the propeller.

Referring to FIG. 9, viewed longitudinally, the front end 59 of thewinglet is attached to the central shaft 25, and the winglet extendsspirally outwardly with an increasing radial width to an outer edge 53until it reaches a maximum circumscribable by an outer, generallycircular envelope T of the dimension of the propeller 11, and then thepropeller 11 grows narrower again at the end of the propeller 11.

As the winglet 41 increases in lateral length, it also develops aconcavity that increases with the length of the lateral dimension S ofthe winglet 41. This curvature is illustrated in the cross-sectionalwinglet diagrams of FIG. 10, taken at progressive longitudinal locationsB₁-B₉ as set out in FIG. 8, and also in enlarged detail in FIG. 11.Cross-sections similar to those are seen in the progressivecross-sections taken normal to the longitudinal axis shown in FIG. 12,which shows the actual propeller cross-sections with all three of thewinglets.

In segment B₁, it may be seen that the winglet projects slightly fromthe central shaft 25 but has no concavity between the inward proximalend 51 and its outward end 53 with both sides 55 and 57 of the wingletbeing essentially planar in this section. At the beginning portion ofthe propeller, at front end 59 of the winglet, the winglet 41 has anarrow lateral or radial dimension between the proximal portion 51 onthe shaft or the axis and the outer edge 53. In this initial portion Aof the winglet through section B, the function of the winglet is to cutinto the fluid or water as the vehicle advances into essentiallyundisturbed water, and the rotation of the propeller has limited effect.As best seen in the detail of FIG. 11, in this initial portion, thewinglet extends at an angle of attack, defined as the direction of theplane bisecting the angle between surfaces 55 and 57, relative to acircle or cylinder around the longitudinal axis that is in a range ofapproximately 85 to 90 degrees. In terms of the spiral around thelongitudinal axis, the winglet fairly immediately curves from parallelto the axis to a spiraling angle of about 45 degrees, or, mostpreferably, at a spiralinWdiagonal angle that is the parallel angle tothe incoming flow of water in this portion. This allows for a lessturbulent engagement of the initial part of the propeller 11 with thewater as the sharp edge 53 of the winglet extends into it. Slightlyfurther rearward at plane B₂, the rearward-facing surface 57 becomesslightly concave, and the curvature is such that the sharp leading edge53 of the winglet 41 begins to extend circumferentially forward relativeto the rotational direction of the propeller, cutting slightly into thefluid and beginning to draw a limited amount of fluid in this area intoconforming flow along inside surface in inward and rearward facingsurface 57. At the same time the curvature of the helical spiral pitchof the surface increases from the initial cutting angle adjacent tofront end 59 which is zero or a very low angle relative to the axis to agenerally diagonal cutting angle of attack as will be discussed below.

Referring to cross-section B₃ of FIG. 10, the surface length from thecentral shaft 25 to the outward edge 53 increases as does the concavityof the rearward and inward facing surface 57. This cross-section area isincreasing the amount of fluid that is being entrained by the leadingedge 53 and brought into the surface 57 to flow therein in a volume orchannel defined generally between the shaft 25 and the outward edge 53of the winglet 41. Initially, the cutting of the edge 53 is to drawwater into this volume or channel space, but it also prevents to somedegree a great deal of laterally outward flow from the propeller 11 dueto centrifugal force and the rotation of propeller 11. As seen in FIG.11, at B₃ the angle of attack of the front surface 55 to a tangent T tothe subtending circle is 35 degrees, or within the range of 30 to 40degrees.

The forward and rearward surfaces extending up to the edge of thewinglet are at an angle in this portion (the intake portion) that causesthe winglet, as the propeller is rotated, to intake water into thechannel behind it smoothly and substantially without cavitation. This isaccomplished by selecting the varying angle of these surface edgeportions such that the edge in the intake portion cuts the water asindicated in FIG. 16. The surfaces 55 and 57 are almost planar in thearea near the edge 53, and are angled relative to each other by an angleα. Line P extends through the edge and bisects the angle α. The wingletedge is positioned so that, as the propeller is rotated, the flow ofwater, as indicated by the arrows, is parallel to the bisecting line P,so that flow is split roughly equally over the front and rear surfaces55 and 57. The surfaces 55 and 57 curve very gradually as they extendaway from the edge, and there is consequently little if any turbulencein this portion of the propeller. In cross-section B₄, the distance Salong the surface 57 from inner shaft 25 to the outward end 53 hasincreased further, as has the concavity of the rearward and inwardfacing surface 57. An entrained volume of water generally illustrated bythe chord 63, which extends from the longitudinal axis to the edge 55 ofwinglet 41, defines the volume inside the winglet 41 which is preventedfrom outward centrifugal lateral radially-outward movement by the shapeof the winglet and the inner surface 57. In addition, the angle formedbetween the outward surface 57 adjacent outward edge 55 and tangent to acircle subtending the winglet cross-section at that point now becomescloser to zero degrees, and the inside surface 55 being a few degreesfrom the tangent. The edge, however, is angles such that the edgecontinues to cut into the water, and brings it into the channel, whichcontinues to increase in cross-section and volume. Due to this angle ofthe edge of the inside surface 57, the fluid in the channel behind thewinglet flows along the surface 57 only in a rearward direction obliqueto the longitudinal axis of the propeller, and any radially outwardcomponent is deflected by the almost tangentially rearward extendinginside surface 55 at the edge 53, eliminating or reducing greatly thecentrifugal loss of fluid the movement of which would be lost kineticenergy.

Referring to cross section B₅, best seen in FIG. 11, the wingletincreases in the length along the surface of surface 57 to the outwardend 53, with the outer surface 55 at the edge being at this pointapproximately zero (0) degrees to the tangent T to the circle subtendingthe winglet cross-section. At this point, the winglet is at its longestlateral surface width. Rotation of the propeller (clockwise in thisview) causes water to conformingly flow into the channel and diagonallyrearward therein, and also to conformingly flow generallycircumferentially over the outer surface 55. The forward facing surface55 generally is convex over its entire surface, except where itconformingly connects near the central shaft 25 and in the initialportions A and B adjacent the front end point of propeller 11. Inaddition, forward surface 55 extends generally obliquely rearwardly atall points

The longitudinal cross-sectional or differential volume of the channelis here at its maximum. As used herein, the cross-sectional area isintended to mean the area of the channel behind the winglet taken in aplane normal to the oblique path of the spiral of the channel. Thatplane may be defined as the plane perpendicular to the rear surface ofthe winglet and extending through the forwardmost point on that surface.Similar to that cross-section is the cross-sectional area of the channelbetween a forwardmost point on the rear surface and the winglet in alongitudinal plane through those points, as seen in, e.g., FIG. 5B. Thatarea is analogous to the flow-path area described above. The volume herereferred to is the differential or instantaneous volume, i.e., therelevant cross-sectional area times a short or differential distance inthe spiral path, and is basically the same as the cross-sectional areadescribed here.

Referring to FIG. 14, the inward surface 57 adjacent the edge 53 is at avery thin angle β, which is made as thin as possible while maintainingstructural integrity of the propeller, this angle being preferably 10degrees or less, and most preferably 5 degrees or less.

The curvature of the winglet is such that in this, the retentionportion, the distance R from the shaft 25 to edge 53 is at least 50% ofthe longitudinal distance Q from the edge 53 to a longitudinallyforwardmost point of the surface 57 defining the channel, and Q ispreferably equal to or greater than R, still relative to the designchosen (or to the thickness of the winglet wall at that point, thethickness of the axle and the kind of curvature/radius) as well as tothe number of winglets chosen and the rotational speed.

Rearward of this section X₅, the volume subtended and enclosed by theinner surface 57 as defined as the space between the chord 65 andsurface 57 begins to decrease in size, and water flowing through thechannel is gradual propelled out of the channel rearwardly. This iscaused by winglet curvature being flattened radially inward, making thechannel squeeze the water to accelerate. The spiral pitch around thelongitudinal axis also steepens in this area, creating a more rearwardangular direction in the flow. In addition, as shown in FIG. 17A, alongitudinal cross-section of the winglet has water being forced againstthe surface 57 by the centrifugal force of rotation and by the pinchingof the channel. The water is driven outward by the centrifugal forcescreated by rotation of the propeller 11, and it passes along the surface57, where it is deflected along surface 57 to flow conformingly thereonand then to flow mainly directed straight rearward from the edge 53 ofthe winglet, which has ceased to be a cutting edge, and has become morea trailing edge, with water flowing out of the channel over it. Due tothe narrowness of angle β, the surface directs the water rearward with aminimal radially outward component.

Referring to the cross-section of plane B₆, after reaching its widestsurface extent at B₅, the channel narrows, but the forward surface 55still extends to edge 53 roughly tangent to the maximal outer circlesize of the envelope, and has a volume defined at a maximal pointbetween the surface 55 and the chord 67 which is entrained so as not tobe able to pass radially outward of the propeller 11 despite anycentrifugal force that is generated by the flow of fluid through thishelical passage. The shape of the concave channel remains generallyarcuate, although reducing in radius, in the transverse cross-sectionshown. In longitudinal cross-section, best seen in FIG. 5A, however, thechannel becomes oblate or oval-shaped, with the shorter axis of the ovaloriented radially of the propeller. The surface length of the rearwardsurface 57 also diminishes rearward of this maximal point more rapidlythan it developed at the front part of the propeller. The surfaceretains its concavity but this is greatly reduced, as is the subtendedspace or volume that is entrained against outward movement by thesurface 57. Similarly, the radial outward end 53 at this point no longeris near tangent to the circle of the subtending circle of thecross-section but is becoming more angled relative thereto. By the pointof cross-section B₆ the concavity is reduced and the inward dimension isreduced so as to more readily release all the water that was retained inthe helical channel of the winglet 41.

Further rearward, the volume reduces rapidly, and also, the wingletreduces in length as well as its arcuate extension, changing the angleof orientation of the edge of the narrowing bladelet. At B₆ thelateral/diagonal cutting angle of attack of the edge remains at about 0degrees to the tangent. Then, at B₇ the lateral/diagonal edge angle ofattack is 20 degrees to the tangent circle. At B₈ it is 37 degrees tothe tangent, and at B₉ it is about 40 degrees to the tangent or at themost convenient/efficient angle to still retain the fluid from beinglost laterally.

Finally, at cross-section B₉ the trailing edge of the winglet 61 shouldbe at the proper angle in order to keep the fluid in here also but itmay just as well diminish to approximately zero at the very end andrelease the last bit of water in the volume that was subtended, althoughthere was some concavity, there is simply a release of this fluidslightly rearward, and the pitch is at approximately zero degreesrelative to the shaft 25 and the longitudinal axis of the propeller.

FIG. 15 graphically illustrates the geometry of the winglets, all threeof which are, as has been stated previously, identical, justrotationally spaced 120 degrees around the axis from each other. Thefront end of the propeller is at the origin. The graph shows twoparameters of each winglet varying over its length from 0 to L. Thecurve φ represents the rotational position around the longitudinal axisof the propeller of the midpoint of the base of the winglet where it isconnected to the shaft 25, and the curve τ represents the rotationalposition for the edge 53 of the winglet. The dimensions and proportionsset out in this graph are exemplary, and may vary substantially from theexample here shown while still providing benefits of the invention.

At the front tip, the midpoint and the edge start aligned and extendinggenerally in a longitudinal direction. Slightly rearward of this, both φand τ gradually curve spirally around the shaft, with a slight angularseparation of about 5 to 15 degrees as the intake portion begins.

The midpoint curve φ only soon extends into a spiraling path defined bya spiral angle φ₁, which is in the embodiment shown 45 degrees, and themidpoint spirals around the axis at this constant angle φ₁ for most ofthe length, until the rearward end, where the spiral pitch of the curveφ increases and the curve φ changes to a steeper angle, e.g., φ₂ whichis approximately 25 degrees to the longitudinal direction. Finally atthe rear end of the propeller, the curve φ gradually bends to alignparallel with the longitudinal axis at the terminal exhaust portion ofthe propeller.

The edge curve τ curves similarly to the φ curve, but is slightlyforward thereof at first, and curves to reach a spiral angle of τ₁,which is about 35 degrees in this embodiment. The edge curve τ continuesat this spiral angle for most of its length, with an extended portion orelongation indicated by the distance of the curve τ to the dotted linecorresponding to the spiral of the base portion midpoint. Near the rearend of the propeller, the winglet edge cuts back at an angle in a rangeof e.g., 40 to 50 degrees, here 48 degrees. At the end of the propeller,the curve r finally bends to parallel with the longitudinal directionand the winglet reduces to a radial length of zero.

The reduction of the spiral angles at the end of the propeller to 0degree or parallel to the longitudinal axis is always desired in orderto correct the vortex as much as possible. However, in variants wheremaximum output or maximum performance in terms of speed, etc. is sought,or when there is no concern about the vortex, the angle may remain thesame as it was for the active/propelling segment, for instance at 45degrees, such as in the embodiment seen in FIG. 80.

The shape of the winglet between the midpoint of the base and the edgeis generally arcuate, preferably an arc centered on a spiral line goingdiagonally around the axis parallel to curve φ, with the arc increasinggradually to the maximum at the retention portion. The arc after thatdeforms laterally to be oval, preferably an oval with a longitudinallength 1.5 to 2 times its lateral width.

The structure, the shape and the curvature and the angles of the cuttingedge of the axial impelpropeller at the intake openings all concur andare synchronized (with each other)—they are all configured so that atany distance from the center the angle of attack of the cutting edge isoriented at the most beneficial and efficient angle for the incomingflows, straight and diagonal, all based on and relative to at least therotational speed, the advancing speed and the other needs and purposesof the design.

As the propeller rotates it forms a certain three dimensional shapewhich, when sectioned through the longitudinal centerline renders a 2-Dside view of its envelope, profile, contour or outline of the propeller,as shown in FIGS. 83A, 83B and 83C.

FIG. 83A shows a general outline view of the envelope of rotatingpropeller 11 of FIGS. 1, 4, and 5A. FIG. 83B shows a general outlineview of the envelope of rotating propeller 85 of FIGS. 19 and 20, and itis also similar to the outline of the envelope of the rotating propellerof FIG. 26. FIG. 83C is a general outline view of the envelope of therotating propeller of FIG. 30.

The penetration/piercing angle of attack alpha of the front part of theprofile of the propeller is half of the angle of attack at which thepropeller pierces and cuts into the fluid at its beginning and center.Unless there is a driveshaft at the front side, it is preferred that thefront point or tip and the alpha angle would be as sharp as possible forthe best penetration. The angles in the illustrations are examples forthese variants.

Generally, it is preferred that in the case of the propeller thepenetration angle starts gradually at 0 degree at the center and then itincreases gradually (as measured at the end of the shoulder or beforeend of the elongation but it is also relative or based on design, needs,requirements, etc.) to 20 to 35 degrees for very fast speed versions; to35 to 50 degrees for fast speed and general purpose, medium speedversions, and so on; with the extreme limits of 10 degrees to 70 degreesfor alpha and a maximum of 80 degrees for the angle beta. In extremehigh speed versions, the alpha angle can be as low as 5 degrees.

For simpler and for fast versions, of streamlined outline, the anglesalpha and beta at the front, and then at the back, gamma and deltaangles may be equal respectively and undistinguishable (that is, alphacan be same as beta and gamma can be same as delta). But for someapplications for wider propellers or of larger volume the outline ismore complex and the two pairs of angles will be more distinct from eachother.

The particular outline view for propeller 11 is shown in FIG. 5B, whilethe particular outline view for propeller 85 is shown in FIG. 23.

The simple transversal cross-sections of the propeller, as those used inthe illustrations presented here, are perpendicular to the propeller'slongitudinal axis and therefore are more elongated or oval since thepropelling angle or the cutting edge or the channel is at an angle tothe longitudinal axis of the propeller, of even 45 degrees.

However, for design and manufacturing purposes, to better understand andto describe more accurately the flow inside the winglet or the channel,the transversal cross-section view of the winglet is preferred to berepresented (also) in a true cross-section that is perpendicular to thepropelling angle/helix or to the cutting edge.

Such a view is made from individual transversal cross-sections which arearranged together in one composite illustration—one for each winglet andthen turned around to the illustration plane (for instance to 45 degreeswhere the angle of attack or the helix is at 45 degrees). Such a viewrepresents more accurately the desired (or the real) shape and curvatureof the winglet.

FIG. 17B represents such a cross-section which also shows how the flowscombine and unite within the channel with the components alreadydiscussed in FIG. 17A, the sectioning being taken at the intake segmentbut very close to the retention segment.

The purpose and aim of the ideal design is to create such a curvature,for the specific given task and conditions of the particular winglet orpropeller, in which the resulting compound combination of the incomingflows (straight and diagonal) in their synchronization develops into asmooth single rotating flow that is the most efficient way oftransporting water inside each channel, as shown in FIG. 17C. This flowat the same time is directed straight backwards.

Therefore it is desired that as the winglets begin to curve, starting atthe segment B, and continuing in segment C, the inside wall of thechannel is as rounded as possible at the root (where it is attached tothe axle), when possible, as in the case of the three winglet designs.When the number of winglets increases there is less space at the rootand therefore less roundness possible,

Further on starting with segment D and then as the channel decreases insize, toward the exit it, is preferred that the interior roundness atthe root (at the base) should change into a narrowed shape so that theindividual twisting inside the channel is restricted and will cease withthe result that the flow will be stabilized from rotating and sentstraight backwards without any rotational movement. A major problem ofpropellers of the prior art is that they create conditions forcavitation, this being, first, peripheral cavitation at the tips of theof the blades, and, second, cavitation at the back of the blades, thisdue to the fact that the blades cut perpendicularly through the water ina sudden movement relative to the stationary fluid. The waterexperiences an abrupt effect or encounter, enhanced by the highperipheral speed of the propeller at its tips compared to the rest ofthe blade body. Cavitation restricts the maximum rotation rate of thepropeller, because above a certain level of revolutions per minute,cavitation begins, resulting in noise, vibration, even chipping of themetal blades themselves and therefore potentially mechanical damages ofthe propeller.

The propeller here shown can be operated at rotational speeds of 30,000rpm or higher without cavitation, which allows the propeller to have arelatively smaller longitudinal cross-section while still being able toproduce a large amount of thrust to the vessel. It also results in amore energy efficient propulsion of the vessel. Additionally, incontrast to prior art propellers, the efficiency of the propeller of thedesign presented here actually increases with the increasing of therotational speed.

FIG. 18 shows an alternate embodiment of support for another very fastpropeller according to the invention. In this embodiment, the propeller71 has a central shaft 73 and winglets 75. The shaft 73 has both frontend 77 and rear end 79 supported on respective pivoting supportconnections 81 and 83. The propeller 71 is rotated by a drive systemsimilar to the drive seen in FIG. 1 connecting through one or both ofthese structures 81 and 83.

FIG. 19 shows another alternate embodiment of propeller of theinvention. Propeller 85 is fixedly mounted on the rear end of a driveshaft 87 connected to and rotated by the motor of the boat, not shown.The propeller 85 is driven so as to rotate clockwise when viewed lookingforward.

This propeller 85 is configured for larger volume of fluid and theslower speeds of larger vessels, where usually energy efficiency issought so as to economize fuel, or regular vessels, and it is shorterand wider than the previous embodiments shown.

This version can be used for fast and medium speed, with a diameterratio to length higher than the version of the very fast speed propeller11. While still a performance propeller (but less so than propeller 11)at smaller diameter and high rotational speeds, because of its diameterto length ratio it also allows for a larger diameter construction, andlower rotational speed, and therefore a larger volume of fluid to bepropelled in the case of vessels of larger dimensions.

The most efficient propelling of fluid as far as energy or fuelconsumption is concerned, is at slowest rotational speed and with thelargest possible diameter, but also with the highest torque, when alarge volume of fluid is moved slowly and with the least energyimparted, and therefore lost, to the exit flow. However, this very samedesign/embodiment but of reduced diameter is still capable of veryefficient propelling at high and very high rotational speeds withoutcavitation.

Propeller 85 is of the very same design and principle as propeller 11,and there are just different proportions and ratios between itsdimensions or features. Both are of very streamlined construction;however the first embodiment is the most streamlined, therefore capableof higher speed performance.

In the case of propeller 85, the benefits of using the design in a largesize at slower speed are that it is very energy efficient, economicaland extremely smooth in its forming of flow. Using this configuration ofpropeller in a smaller size, with a smaller diameter about itslongitudinal axis and at a very fast speed, is that it is efficient inattaining very high vessel speeds while still avoiding the flaws ofprior art propellers.

Because the propeller 85 is radially wider, the edges of the wingletsare farther away and the actual speed of the edges of the blade whenrotated is higher. For a prior-art propeller, the higher the speed ofwater flow, the greater is the possibility of cavitation, which is veryundesirable in the propeller environment. Also, the wider propeller maycreate more drag due to its larger external envelope. However, with theembodiment shown, even when constructed with a larger diameter andmoving larger volumes of fluid at higher rotational speed of the edges,cavitation still does not occur.

For all top-performance boats that use gas turbines, which can run ataround 20,000 rpms or higher, the propeller can be connected directly toa turbine without a need for reducing gears or other torque or speedreducers.

FIGS. 20 to 22 show the propeller 85 in greater detail. The propeller 85is a unibody structure as defined above with central shaft 87 supportingthree winglets or blade surfaces 91, 93 and 95 thereon, each rotativelystaggered or distributed at 120 degrees of rotation about the centrallongitudinal axis. Each winglet has a respective forward facing surface97 and a respective rearward facing surface 99 that meet at a generallyspiraling edge 101. The winglet 91, 93 and 95 are similar to those ofthe previous embodiment in that the emerge from the shaft 87, widenradially, and then taper inwardly to merge into the shaft 87 at the rearof the propeller 85, which ends in a sharp longitudinal point 103, whichreduces turbulence trailing behind the propeller 85.

The configuration of the winglets 91, 93 and 95 is best shown in FIGS.23, 24A and 24B. As with the previous embodiment, the winglets initiallybegin to extend radially outward and run longitudinally rearward in theforward portion B. As the winglets lengthen radially, they becomeconcave and then begin to spiral in the direction away from theirconcavity, each defining a respective rear facing channel space.

As with the previous embodiment, rearward of the front portion starts anintake portion, from roughly cross-sections C₃ to C₈ in FIG. 23. In thisintake portion, the winglets increase in length and the cutting angle ofedge 101 relative to a tangent circle about the axis of rotation untilthe outer surface 97 at the edge 101 is tangent to a cylinder around thelongitudinal axis. The winglet surfaces are at angles such that the flowof water on the front and rear surfaces 97 and 99 is a substantiallycavitation-free conforming flow, with the flow of water passing into thechannels and over the forward surfaces 97. The channel space enclosed bythe winglets increases monotonically and continuously rearwardlythroughout the intake portion.

The lengthening of the winglets continues through a retention portion atroughly sections C₈ to C₉ (rather to C₁₁), where the edge 101 goes froma cutting edge to a trailing edge with water flowing over it out of thechannel. The channel remains the same configuration in terms of relativeproportions, although the volume enclosed may increase as the length ofthe winglet and the diameter of the propeller increase. Due to the moreabrupt inward tapering of the propeller 85 at its rear portion, theinside surface and even the outside surface at the trailing edge areangulated rearward and inward slightly, allowing exterior flow of waterover surface 97 to be directed slightly inward radially at e.g., 5 or 10degrees to longitudinal. Similarly, the inside surface 99 also directsthe flow rearward and slightly inward.

The radially inward angle is only relative to the longitudinaldirection. From the cross-section normal to the longitudinal axis at C₈or C₉ in FIGS. 24A and 24B, it can readily be seen that adjacent theedge 101 ends with the transverse cross-section of the outer surface 97at about 0 degrees to the tangent to a cylinder about the longitudinalaxis at that point. This maintains conforming flow while the propellerrotates, and also retains the water in the channel against centrifugalloss in this retention portion. The winglets extend beyond an arc of 180degrees to include an extended portion 105 that essentially has anarcuate curvature with a radius equal to the radial distance to thelongitudinal axis of the propeller, instead of curving around a curveapproximating an arc with a radius of the enclosed passage, as in theradially inward portion 107.

In the exhaust portion, seen in cross-sections C₉ to C₁₀, the radiallyoutward distance to the edge 101 decreases, and the length of thelarger-arc-shaped portion 107 of the winglets begins to shorten,reducing the volume in the channel, which propels the water thereinrearward, as in the previous embodiment. The elongated larger-arc-shapedportion 107 diminishes with the radial size of the winglets until, atcross-section C₁₄, the winglet is simply the curvature of the channelpassage, i.e., smaller-arc-shaped portion 107. Rearward of this, thewinglets then taper down rapidly to just the shaft at its end 103.

FIG. 25 shows a variant of the embodiment of FIG. 19, wherein thepropeller 104 is supported by a rotating drive shaft structure 109connected with the rear end of the central shaft 108, in a configurationsimilar in general to FIG. 1. The front end of the propeller 104 isprovided in this embodiment with a pointed end 106, similar to end 23 ofpropeller 11, that pierces into the water without turbulence.

FIG. 26 is a side view of still another embodiment of propeller systemsimilar in many ways to propeller 85, with similar characteristics andperformance. FIG. 27 is a front view and FIG. 28 is a forward-lookingrear view taken from plane B-B of FIG. 26. FIG. 29 is a cross-sectionalside view with an outline of propeller of FIG. 26 taken through avertical plane extending through its axis of rotation.

Working similarly to propeller 85, the propeller 110 has a tip 111 thatpierces the water at its front end, and winglets 115, 116 and 117, whichare all supported on and driven by shaft 112, which is connected to adrive system (not shown). The propeller 110 is driven so as to rotateclockwise when viewed looking forward. The propeller 110 has an outwardenvelope contour that is more gradual than the previous embodiment.

FIG. 30 is a side view of another embodiment, a five winglet propellerwith a conical entry portion that slopes outward at approximately 45degrees. The propeller has a larger diameter and a more abrupt outline(or penetration and ending angle). This propeller is a medium speedversion that can be used for heavy work, with a larger diameter and ashorter length than the previous embodiments, configured less for speedthan for high torque. FIG. 31 is a front view and FIG. 32 is a rear viewof the embodiment. FIG. 33 is a cross-sectional side view with outlinetaken through a vertical plane extending through its axis of rotation.FIG. 34 shows cross-sections at planes D₁-D₄ of the propeller. Workingon principles similar to those of propeller 85, this embodiment has ashaft 121 at the front of which the winglets 125, 126, 127, 128 and 129are all supported the rear shaft 122. Any of these shafts can beconnected to the drive system and the propeller is driven so as torotate clockwise when viewed looking forward.

FIG. 35 shows the cross-sections in planes E₁-E₈ of another embodimentthat is a structural variant of propeller 85. All parts and dimensionsof the embodiment are substantially the same as in propeller 85, forpurposes mainly of better equalization of the fluid and pressure thereis a slight bulging of the wall at its outer edge. The cross-sectionsE₁-E₄ show the evolution of the wall thickening for winglets 135, 136and 137. From cross-section E₅ rearward, the wall structure hasessentially the same structure as propeller 85. The propeller is drivenso as to rotate clockwise when viewed looking forward.

FIG. 36 shows the cross-sections F₁-F₈ of still another variant ofVersion 2, propeller 85. Everything is similar to the configuration ofpropeller 85, but the winglet wall is configured to be thicker at itsstart as shown in the cross-sections. For purposes of equalization offluid pressure there is a bulging of the wall at its beginning, as seenin cross-sections F₁-F₄ show the evolution of the wall thickening forwinglets 145, 146 and 147. From cross-section F₅ rearward, the propellerstructure winglets are similar to propeller 85, with relatively sharptrailing edges.

FIG. 37 is the side view of still another embodiment of propeller systemfor a propeller configured similarly to propeller 11, housed in awaterjet configuration for high speed or general purpose. Thisenvironment houses a three winglet propeller such as propeller 11, withthe main propelling angle at 45 degrees. The structural housing for thepropeller has all the components of a typical waterjet set up, i.e., anintake opening, built-in construction and aft stabilizing or correctingblades or vanes, among others, all in the proper adaptation for apropeller configured like propeller 11, with a longer profile and foruse at higher rotational and advancing speeds.

FIG. 38 is a front view and FIG. 39 is a rear view of the embodiment ofFIG. 37 showing the inside of the generally tubular interior passage ofthe water jet structure. FIG. 40 is a cross-sectional view taken througha vertical plane extending through the axis of rotation of thepropeller. FIG. 41 shows cross-sections of the propeller and surroundingstructure of FIG. 37 at the planes G₁-G₅ perpendicular to the rotationalaxis of the propeller, as shown in FIG. 40.

As best seen in FIGS. 37 and 40, a vessel 159 floating in water 150 tomove in direction 158 has a waterjet enclosure 152, with intake opening153 at its front and exit outlet 155 at its rear end. Within enclosure152, the structure of the waterjet system comprises propeller 11 a,which differs from the propeller 11 (see FIG. 1) in that it is supportedrotatively at both its front and rear ends, and does not have a point atits front end, but is connected to shaft 151 and through it also to adrive system positioned ahead of the propulsion compartment. The rearend of the propeller 11 a is supported for free rotation in the rearportion of the waterjet enclosure 152. The propeller 11 a is driven soas to rotate clockwise when viewed looking forward.

Water is absorbed through the intake 153 by the propeller 11 a by itsrotation and is stabilized by the eight stabilizing vanes 154, which atthe end also direct the exiting flow rearwardly, which is propelledthrough the exit outlet 155 and propelled straight to the back.

FIG. 42 is the side view of another embodiment of propeller, which is avery high speed or ultra-high speed variant of a three winglet propellersimilar to propeller 11 of FIG. 1, with a main propelling angle at 45degrees, but with an intubation 163.

The propeller of FIG. 42 is structurally similar to propeller 11, but atits rear portion intubation 163 is attached, starting at theapproximately the point of the largest diameter of the winglets 165, 166and 167 and rearward therefrom so as to aid in directing the rearwardexpulsion of water from the propeller. The intubation is a rearwardlytapering truncated cone that forms a round channel or tapering conicalinner passage in which all the individual flows from the winglets arecombined. The intubation structure 163 at the same time maximizes theconcentration of the exit flow to the smallest cross-section possiblethrough the exit outlet 164. The outer surface shape of a taperingtruncated cone also reduces even more any drag, making theimpelpropeller structure even more streamlined and therefore maximizingthe overall performance of the propeller 11.

Intubation 163 has a gradual intake opening defined by a sharp leadingedge. The intubation conforms and adapts to the shape of the winglets,this in order to create less resistance at the intake openings, and hasconfirming water flow over the leading edges defining the intakeopenings. This design is best adapted for very high speeds.

FIG. 43 is the front view and FIG. 44 is the rear view of the sameembodiment. FIG. 45A is a cross-sectional view with outline takenthrough a vertical plane extending through its axis of rotation. FIG. 46shows cross-sections H₁-H₁₄ which are the same as for propeller 11 butwith the addition of the intubation 163. Based on the same structure aspropeller 11 of FIG. 1, this embodiment has the front tip 161 and thewinglets 165, 166 and 167 which are all being supported by the rearshaft 162 which is connected to the drive system. The propeller isdriven so as to rotate clockwise when viewed looking forward.

FIG. 47 is the side view of still another propeller embodiment similarto the propeller of FIG. 30. It is an example of a five-wingletpropeller with a propelling segment angle of 45 degrees, of a largerdiameter and with a more abrupt or less acute envelope outlinepenetration and ending angle, but with a short intubation 173 instead ofelongation, of equal length to the elongation of the propeller of FIG.30. The propeller of FIG. 47 can be used for same duties, and it has aperformance similar to that of the propeller of FIG. 30.

FIG. 48 is a front view and FIG. 49 is a rear view of the propeller ofFIG. 47. FIG. 50 is a cross-sectional view with an outline taken througha vertical plane extending through its axis of rotation. FIG. 51 showscross-sections IA perpendicular to the axis of rotation of the propellerof FIG. 47. The intubation 173 has a round intake opening at its frontwith a sharp leading edge around it, as well as a round exit outlet atthe back 174 with a sharp trailing edge around it. The outer and innersurfaces of the intubation are curved and generally follow the curvatureof the outer envelope of the propeller.

Working on the similar principles to those of propeller 85, thisembodiment has a front shaft 171 extending through the propeller to therear shaft 172, on which winglets 175, 176, 177, 178 and 179 are allsupported. Either or both of the shafts 171 and 172 are connected to thedrive system, and the propeller is driven so as to rotate clockwise whenviewed looking forward from the rear.

FIG. 52 is a side view of a backwardly and forwardly symmetrical,reversible embodiment of propeller, with a T-section of the wingletedges. This embodiment can be used to drive a vessel in eitherdirection, forward or rearward, and it is designed for either high orregular speed. Since it is rear/forward symmetrical, its efficiency isthe same in either direction.

FIG. 53 is a front view and FIG. 54 is a rear view of the propeller ofFIG. 52. FIG. 55 is a cross-sectional view, with the envelope of therotating propeller as an outline, taken through a vertical planeextending through its axis of rotation. FIG. 56 shows cross-sectionsJ₁-J₉ perpendicular to the axis of rotation of propeller of FIG. 52.Winglets 185, 186 and 187 are structured in such way that either halfcan be directed forward or rearward, and each half is a reflection ofthe other half. Because the elongation runs (longitudinally) on bothsides of the cutting edge, at the center the cutting edge forms aT-section cross-section 184, as best seen in cross-section H₅ of FIG.56, or in the longitudinal cross-section of FIG. 55. The winglets areattached at one end to the shaft 181 and to the shaft 182 at the other,and either shaft can be connected to a drive system.

Rotation can be both ways. For the configuration of winglet structureshown, the advancing (front) end is given by the clockwise rotation ofthe propeller as looked forward from the other end, and thisconfiguration may be described as a right-hand propeller.

FIG. 57 is the side view of still another embodiment of propeller, ageneral purpose propeller with a bulbous nose and small intubation,which replaces the elongation of the propeller. This propeller is suitedfor use at high or regular speed.

FIG. 58 is a front view and FIG. 59 is a rear view of the embodiment ofFIG. 57. FIG. 60 is a cross-sectional view with the rotational envelopeshown as phantom outline, and taken through a vertical plane extendingthrough the axis of rotation. FIG. 61 shows perpendicular cross-sectionsK₁-K₉ of the propeller of FIG. 57. As seen in FIGS. 57 and 60, asomewhat bulbous nose 191 is in the front part from which winglets 195,196 and 197 start. The winglets 195, 196 and 197 are connected at theirlargest diameter with the small intubation 193, which has an roundintake opening 190 and a round exit outlet 194, with interveningstructure with an outer surface and an inner passageway surface thatgenerally follows the rotational envelope contour of the propeller. Theentire structure is supported and connected by the shaft 192 to a drivesystem, and driven so as to rotate clockwise when viewed lookingforward. FIG. 62 is a side view of another embodiment with wingletsattached around a shaft that is a solid shape that tapers radially widerat the exhaust portion of the propeller, and then tapers inwardlyrearward of that, as best shown by FIGS. 62 to 66. The exit outlet ofthe winglet channels is wide, being at the periphery of the widest partof the solid shape. The propeller is a three winglet propeller with apropelling segment angle of 45 degrees, with elongation. The wider exitoutlet produces greater acceleration because the exit flow is expandedlaterally. This embodiment is suited for high or regular speed andperformance.

FIG. 63 shows a front view and FIG. 64 is a rear view of the propeller.FIG. 65 is a cross-sectional view with a rotational envelope outline andtaken through a vertical plane extending through its axis of rotation.FIG. 66 shows perpendicular cross-sections L₁-L₉. Winglets 205, 206 and207 start at the front shaft 201 at the front and are then attached tothe solid shape 208, which tapers radially outward and then inward,where it ends at shaft 202. Either of the shafts 201 or 202 may beconnected to a drive system. The fluid is propelled backwards, but alsoslightly laterally outward at approximately the location of the L₆cross-section. The propeller is driven so as to rotate clockwise whenviewed looking forward.

FIG. 67 shows a side view of a version of a propeller similar topropeller 11 but enclosed and rotatingly attached at both its endswithin a fixed, non-rotating frame or grille 211. The front or rear endsof the propeller are connected with a shaft extending through the frameto a drive system that rotates the propeller inside the frame. The framestabilizes the flow inside and outside of the enclosed propeller.

The fixed frame 211 in this version has vanes that start straight andparallel to the longitudinal axis, but then, in the middle section, areoriented at a counter angle to the rotation of the rotating propeller11. Before the rearward end, the vanes become straight again. There isan intubation 213 at the middle of the frame on the outside which alsoconsolidates the frame 211. The embodiment with such a frame can beattached to a vessel at its ends or at the intubation 213.

The frame 211 maintains a straight incoming flow towards and around theintake outlets and at the end it corrects the flow at its exit outlets,while the intubation 213 at the middle keeps the flow inside andmaintains the streamlines around its body. It also protects the rotatingpropeller within it. This system is suitable for either high or regularspeeds.

Alternatively, the entire vane structure of the frame may be straightand parallel to the longitudinal axis of the propeller.

FIG. 68 is a front view of the propeller of FIG. 67. FIG. 69 shows thepropeller mounted within the frame 211, which is sectioned along itslongitudinal centerline, and FIG. 70 shows a rear view of the propellersystem of FIG. 67.

FIG. 71 shows perpendicular cross-sections M₁-M₆ of the propeller ofFIG. 67. The rotation of the propeller within the frame is clockwise asviewed from the rear.

FIG. 72 shows another embodiment of propeller system similar to that ofFIGS. 67 to 71 in a longitudinal cross-sectional view. FIG. 73 shows afront view and FIG. 74 shows a rear view of the propeller system of FIG.72. The vanes of the first half of the frame 212 ends where theintubation 214 starts, and vanes of a second half of the frame continuerearwardly from where the intubation 214 ends. The intubation 214 ispositioned closer to propeller 11 than in the embodiment of FIG. 67. Therotation of the axial impelpropeller 11 within the frame is clockwise asviewed from the rear.

FIG. 75 shows a side view of a reversible, symmetrical, corelesspropeller embodiment that has hollowed-out winglets at the center, thepropeller being attached at its ends to rotating shafts 221 and 222. Itis a three winglet propeller with a propelling segment with an angle ofattack of 45 degrees, with a slight elongation. Because the propeller isreversible and symmetrical, it can run in both directions with the sameefficiency and can be used for high or regular speed and performance.

FIG. 76 shows a front view and FIG. 77 shows a rear view of thepropeller of FIG. 75.

FIG. 78 is a longitudinal cross-sectional view with rotational envelopeoutline of the propeller of FIG. 75 taken through a vertical planeextending through its axis of rotation. FIG. 79 shows perpendicularplanar cross-sections N₁-N₉ of the propeller. The winglets 225, 226 and227 are structured so that either half can be directed forward orrearward, and each half is a reflection of the other half. At thelongitudinal center, the cutting edge of the winglets 225, 226 and 227forms a flat section with double-edges in cross-section, as best seen inthe cross-section N₅ of FIG. 79. Because the winglets are reversiblethey do not have an elongation. The winglets 225, 226 and 227 areattached at one end to the shaft 221 and to the shaft 222 at the other,and either shaft can be connected to the drive system. Rotation can beeither clockwise or counterclockwise. For the configuration of wingletstructure shown, the advancing (front) end is given by the clockwiserotation of the propeller as looked forward from the other end, and thisembodiment can be described as a right-hand propeller.

FIG. 80 is a side view of still another embodiment of propeller, for useat a very high speed or ultra-high speed. The propeller shown is amodification of propeller 11 (see FIG. 1), with the rear half beingintubated, which replaces the elongation, similar to propeller of FIG.42. A difference of this embodiment is that there is no tapering of thesecond half of the winglets outline at its rear end, as there is noconcern to control or correct the exit vortex flow.

Rather, the winglets continue to the end at the same 45 degree angle ofattack all the way to the end, in order to maximize the propulsion. Theembodiment shown is particularly suited for performance and speed. Theintubation concentrates the exit flow and at the same time streamlinesthe outside flow forming around its body for faster advancing speed.

The front view of this embodiment is the same as that shown in FIG. 43of the propeller of FIG. 42. FIG. 82 shows cross-sections O₁-O₅ of thepropeller of FIG. 80 perpendicular to its axis of rotation. FIG. 81 is alongitudinal cross-sectional view with outline of the propeller of FIG.80 taken through a vertical plane extending through its axis ofrotation. The first half (to the start of the intubation is thesubstantially the same as propeller 11 of FIG. 1. The winglets 235, 236and 237 start at the front tip 231 and end at the shaft 232, which isconnected to a drive system. The intubation 233 maximizes theconcentration of the exit flow to the smallest cross-section possible,with the exit outlet 240, thus reducing even more any drag, making itsstructure even more streamlined and therefore maximizing the overallperformance of the propeller 11.

Intubation 233 has a gradual intake which conforms to the shape of thewinglets, in order to create less resistance. This design is suitedparticularly for very high performance and super-high speeds. Thepropeller is driven so as to rotate clockwise when viewed lookingforward.

Other structures may be envisioned that employ winglets with intake andexhaust portions, with a retention portion therebetween whereappropriate. Also other purposes may be achieved by the fluid propellingdesigns of the present invention other than moving vessels on water,such as accelerating fluids in containers in the chemical industrycontext, or other environments where efficient movement of liquids isdesirable.

As pumps are essentially enclosed propellers, a variety of axial pumpscan be designed based on the principles and designs presented here, withthe inclusion of all the necessary additional parts such as the pumphousing, enclosure or chambers, directional or correcting vanes, etc.

The foregoing description is illustrative of the present invention andshould not be considered as limiting, and the terms of this disclosureshould be seen to be terms of description rather than limitation, asmodifications and changes to the invention should be readily apparent tothose having ordinary skill in the art with this disclosure before them,which modifications would not depart from the spirit and scope of theinvention.

What is claimed is:
 1. A propeller supported on a floating body so as tobe substantially completely submerged in water and rotatable about anaxis of rotation to propel the floating body in said water in a forwarddirection of movement, said propeller comprising: a plurality ofwinglets supported on the floating body for rotation about the axis ofrotation; each of said winglets extending in a generally spiral pathabout the axis of rotation and having a first surface facing generallyrearwardly and a second surface facing generally forwardly; the firstsurface of each winglet and the second surface of a respective nextadjacent one of the winglets defining therebetween a fluid passage spaceextending generally spirally around the axis of rotation, said fluidpassage space having a varying volume defined as a space radially inwardof the winglet; in a forward portion of the winglet, the volume of thefluid passage space continuously increasing rearwardly, and in arearward portion of the winglet, the volume of the fluid passage spacereducing continuously rearwardly.
 2. The propeller according to claim 1,wherein the winglets are fixedly supported on a longitudinally extendingshaft overlying the axis of rotation.
 3. The propeller according toclaim 1, wherein the first surface extends from a radially inwardproximal end portion adjacent the axis of rotation to a radially outwarddistal end portion spaced rearwardly and radially outward therefrom, andsaid first surface is concave between the proximal and distal endportions over at least a longitudinal portion of the propeller.
 4. Thepropeller according to claim 3, wherein the first surface extendsrearwardly so that in a longitudinal portion between the forward andrearward portions, the first surface radially inwardly encloses at leasthalf of the fluid passage space defined so that water in the fluidpassage space is entrained by the first surface against radially outwardmovement away from the propeller, and the first surface has across-section taken along a centerline of the fluid passage space thatis substantially a partial circular or oval shape.
 5. The propelleraccording to claim 3, wherein the first surface at the distal endportion thereof extends outwardly and rearwardly at a sloping angle ofless than 10 degrees relative to the axis of rotation such that waterexpelled outwardly of the propeller is caused to flow along the firstsurface and is directed rearwardly.
 6. The propeller according to claim3, wherein the first surface extends outwardly and rearwardly at anangle of approximately zero degrees relative to the axis of rotationsuch that water moved radially outwardly of the propeller is caused toflow along the first surface and is re-directed rearwardly.
 7. Thepropeller according to claim 3, wherein the second surface has aproximal end portion adjacent the axis of rotation and a distal endportion rearward and radially outward thereof, said second surface beingforwardly convex between the proximal and distal end portions over atleast said longitudinal portion of the propeller.
 8. The propelleraccording to claim 3, wherein the first surface of the winglet has alength along said surface, and the length increases from an initiallength of zero or near zero at a longitudinally forward end of thewinglet to a maximal length at a longitudinally intermediate location ofthe winglet, and then reduces to a terminal length of zero or near zeroat the longitudinally rearward end thereof.
 9. The propeller accordingto claim 8, wherein the first surface is generally flat in cross-sectionat the longitudinally forward end and is concave over the entire lengthin the intermediate location.
 10. The propeller according to claim 8,wherein the first surface encloses at least 50% of the cross-sectionalarea of the fluid passage space in the longitudinally intermediatelocation and rearward thereof, and encloses less than 50% of the volumeof the fluid passage space forward thereof, so that the wingletencounters and collects water in the fluid passage space in a forwardportion thereof, and entrains and expels water in a rearward portion ofthe winglet.
 11. The propeller according to claim 1, wherein said theplurality of winglets comprises three winglets.
 12. The propelleraccording to claim 1, wherein the fluid passage space extends spirallyaround the axis of rotation in a spiral path having a pitch, said pitchincreasing rearwardly of the winglet.
 13. The propeller according toclaim 1, wherein the winglets support thereon a generally tubular outerstructure surrounding the winglets and supported for rotation therewith,said tubular outer structure having an inward surface defining apassageway and directing flow of water moved by the winglets in arearward direction through said passageway, said tubular outer structurebeing generally conical and tapering rearwardly to a rear portiondefining a generally circular outlet therein.
 14. A propeller supportedon a floating body so as to be completely submerged in water androtatable about a longitudinal axis of rotation for propelling thefloating body in said water, said propeller comprising: a shaftrotatably supported on the floating body, said shaft having a forwardfront end and a rearward back end, and said shaft being driven so as torotate about the longitudinal axis; and three propulsion structuressupported on and extending in a generally spiral path about said shaftand rotationally staggered with respect to one another; each of saidpropulsion structures having a fluid contact surface with a surfacewidth measured along the fluid contact surface from a radially inwardend portion to a outward edge portion; said fluid contact surface havinga forward engaging portion, an intermediate fluid entraining portion,and a rearward exhaust portion; the surface width of the fluid contactsurface increasing from the engaging portion to the intermediate fluidentraining portion, and decreasing from the intermediate fluidentraining portion to the exhaust portion; the fluid contact surface inthe intermediate fluid entraining portion being concave and inwardly andrearwardly disposed so as to radially inwardly enclose a spiral fluidflow volume, with said fluid contact surface being shaped such thatcross-sections thereof in a plane perpendicular to the longitudinal axisextend curvingly rearward a distance at least as great as a radiallyoutward extension distance of the fluid contact surface.
 15. Theinvention according to claim 14, wherein the spiral path of thepropulsion structures increases in pitch from the intermediateentraining portion to the exhaust portion.
 16. The invention accordingto claim 14, wherein the propulsion structures are rotatively staggeredby approximately 120 degrees of rotation about the axis of rotationrelative to one other.
 17. The invention according to claim 14, whereinthe surface width of fluid contact surface taperingly increases from theforward engagement portion of the propulsion structure to a maximalsurface width in the intermediate entraining portion at a point that isapproximately 0.6 to 0.8 L from the forward end of the propulsionstructure, where L is an overall longitudinal length of the propulsionstructure.
 18. The invention according to claim 17, wherein the surfacewidth of fluid contact surface taperingly decreases from said maximalsurface width to about zero at the rearward end of the propulsionstructure.
 19. The invention according to claim 14, wherein said fluidcontact surface is shaped such that cross-sections thereof in a planeperpendicular to the longitudinal axis extend curvingly rearward adistance at least 1.5 times as great as the radially outward extensiondistance of the fluid contact surface.
 20. The invention according toclaim 14, wherein the cross-section of the propulsion structure in theintermediate portion has a distal outward end, and the fluid entrainingsurface forms an inward angle to a tangent to a circle about thelongitudinal axis of 0 to 5 degrees.
 21. A propeller supported on afloating body in water so as to impel said floating body in a forwarddirection of movement, said propeller comprising: a plurality ofwinglets supported fixedly with respect to each other so as to rotatetogether about a longitudinally extending axis of rotation; each of saidwinglets comprising a winglet body portion extending generally spirallyabout said axis of rotation and having a generally forwardly-disposedforward surface and a generally rearwardly-disposed rearward surface,said forward and rearward surfaces meeting in an acute-angle wingletedge that also extends generally spirally about said axis of rotation;the rearward surface being concave over at least a longitudinal portionof a longitudinal length of the winglet so as to define a generallyrearward facing channel rearward of the winglet body portion such thatthe rearwardly concave rearward surface has a forwardmost channelsurface portion at a forwardmost part of the channel; the longitudinalportion including a forward intake portion, a retention portion rearwardthereof, and an expelling portion rearward of the retention portion;wherein, in the intake portion, the winglet edge is oriented such that,as the propeller is rotated, the winglet edge passes into the water witha conforming flow from the winglet edge over the forward and rearwardsurfaces, and a portion of the water flows into the channel, andwherein, from the intake portion to the retaining portion, theforwardmost channel surface portion of the rearward surface and thewinglet edge extend continuously obliquely rearward, the winglet edgeextending continuously obliquely rearwardly more steeply relative thanthe forwardmost channel surface portion, and the rearward surface widensand defines the channel to as to be wider in the retaining portion;wherein, in the retaining portion, the winglet edge is oriented suchthat the rearward surface contiguous thereto extends rearward in adirection that differs from the longitudinal direction by no more thanthe acute angle; and wherein, in the expelling portion, the channelbecomes narrower than in the retention portion.
 22. The propelleraccording to claim 21, wherein the winglets are fixedly attached to acentral shaft of the propeller and extend laterally outward therefrom.23. The propeller according to claim 21, wherein the winglets define apropeller contour that conically tapers outward in the intake portionand narrows radially inward and rearwardly in the expelling portion. 24.The propeller according to claim 21, wherein the forwardmost surfaceportion extends more steeply rearwardly.
 25. The propeller according toclaim 21, wherein the winglets are fixedly supported on an interiorsurface of a tubular propeller structure, and extend radially inwardtherefrom.